Surfactant protein D (SP-D) is an important innate immune collectin involved in uptake and clearance of microbes and allergens in the lungs. SP-D has been shown to ameliorate allergic asthma reactions in mice; however, the mechanisms for this are not fully understood. We investigated the role of SP-D in the uptake and clearance of the model allergen ovalbumin (OVA) by macrophages. We discovered that SP-D does not bind OVA but binds fractions with contaminating proteins; ovomucin and ovomacroglobulin. We extended these findings to show that SP-D binds human alpha-2-macroglobulin (A2M) in its cleaved or intact state, in a concentration-, calcium-, and carbohydrate-dependent manner. A2M increases the innate immune potential of SP-D by increasing its ability to agglutinate the bacteria Escherichia coli and Bacillus subtilis. We found that SP-D does not increase the uptake of OVA by murine macrophage cell lines, or by alveolar macrophages in vivo in BALB/cJ mice.

Zugl.: Giessen, Univ., Diss., 2008

Universiẗat, Diss., 2003--Würzburg.

No description available.

In der vorliegenden Arbeit wurde der Einfluss der humanen AT2-Rezeptorexpression und -stimulation auf den Collagen I alpha 2-mRNA-Gehalt und die Migration von porcinen kardialen Fibroblasten untersucht, um die Frage zu klären, ob AT2-Rezeptoren in kultivierten kardialen Fibroblasten AT1-antagonistische antifibrotische und migrationshemmende Effekte auf den Collagen I alpha 2-mRNA-Gehalt bzw. die Migration ausüben. Um die Funktion der AT2-Rezeptoren in der Zellkultur untersuchen zu können, wurde die AT2-cDNA durch adenovirale Transduktion in die Fibroblasten übertragen und so der AT2-Rezeptor überexprimiert. Mittels RT-PCR wurden die relativen Änderungen im Collagen I alpha 2-mRNA-Gehalt in TGF-beta1- bzw. TGF-beta1 plus Ang II-stimulierten Fibroblasten im Vergleich zur unstimulierten Kontrolle bestimmt. Alle Werte wurden auf ein Referenzgen (beta-Actin) bezogen. Die AT2-Stimulation änderte den relativen Collagen I alpha 2-mRNA-Gehalt der Fibroblasten nicht signifikant gegenüber den Antisense-(Ad5TA2)-transduzierten Fibroblasten. In der modifizierten Boyden-Kammer wurde der AT2-vermittelte Effekt von Ang II, hPDGF-BB sowie der Kombination beider Stoffe auf die Migration untersucht. Die alleinige Stimulation von AT2-Rezeptoren mit Ang II verhinderte die Migration gegenüber nichttransduzierten Fibroblasten. In Kombination mit hPDGF-BB änderte Ang II die Migration in AT2-überexprimierenden Fibroblasten nicht gegenüber den Antisense-(Ad5TA2)-transduzierten Fibroblasten. Bei ausschließlicher Stimulation durch hPDGF-BB wurde aber in AT2-exprimierenden Fibroblasten eine signifikant geringere Migration als in Antisense-(Ad5TA2)-transduzierten Fibroblasten festgestellt. Die zugrunde liegende Hypothese, dass AT2-Expression und Stimulation den relativen Collagen I alpha 2-mRNA-Gehalt hemmt, konnte in den vorliegenden Experimenten nicht bestätigt werden. Dies ließ keine inhibitorische AT2-vermittelte Wirkung von Ang II im Bezug auf den TGF-beta1-induzierten Collagen I alpha 2-mRNA-Gehalt erkennen. Dagegen führte die Ang II-Stimulation überexprimierter AT2-Rezeptoren zu einer verringerten Migration und vermittelte so einen AT1-antagonistischen Effekt. / In this work the influence of expression and stimulation of the human AT2 receptor on Collagen I alpha 2-mRNA-content and migration of porcine cardiac fibroblastst was tested to clarify the question if AT2 receptors promote AT1 antagonistic antifibrotic and antimigratory effects on collagen I alpha 2-mRNA content and migration. To examine the AT2 receptor function in the cell culture AT2 cDNA was transferred into fibroblasts by adenoviral transduction and the AT2 receptor was overexpressed. Through the use of RT-PCR the relative changes in collagen I alpha 2-mRNA content in TGF-beta1 stimulated and TGF-beta1 plus Ang II stimulated fibroblasts were assayed and compared to the unstimulated control. All values were referred to a reference gene (beta-actin). Stimulation of AT2 receptors did not change the relative collagen I alpha 2-mRNA content of the fibroblasts significantly compared to antisense-(Ad5TA2) transduced fibroblasts. In the modified Boyden-chamber the AT2 mediated effect of Ang II, hPDGF-BB and the combination of both on migration was assessed. The stimulation of AT2 receptors with Ang II inhibited migration compared to nontransduced fibroblasts. In combination with hPDGF-BB Ang II did not change the migration in AT2 overexpressing fibroblasts compared to antisense-(Ad5TA2)-transduced fibroblasts. In the case of exclusive stimulation of AT2-expressing fibroblasts with hPDGF-BB a significantly lower migration was found compared to antisense-(Ad5TA2)-transduced fibroblasts. The underlying therory that AT2 expression and stimulation inhibits the relative collagen I alpha 2-mRNA content could not be confirmed in this work. This did not reveal an inhibitory AT2 mediated effect of Ang II in respect to the TGF-beta1 induced collagen I alpha 2-mRNA content. In contrast to that Ang II stimulation of overexpressed AT2 receptors led to a decreased migration and mediated an AT1 antagonistic effect.

Uma das alterações comuns na sepse são os distúrbios microcirculatórios podem ocorrer mesmo com parâmetros macro hemodinâmicos normais. Vários protocolos são indicados para a anestesia de paciente em sepse. Um fármaco geralmente utilizado em pacientes críticos em humanos é a dexmedetomidina, um potente e seletivo alfa 2 agonista com propriedade sedativas, analgésicas e relaxante muscular que promove aumento de pressão arterial e vasoconstrição periférica. O objetivo do presente estudo é avaliar comparativamente a infusão contínua da dexmedetomidina versus fentanil em cadelas sépticas no que diz respeito a três parâmetros relacionados a microcirculação, parâmetros hemodinâmicos e metabólicos. Foram avaliadas 33 cadelas com piometra submetidas à cirurgia terapêutica de OSH, e triadas pelo score quick SOFA. Os animais foram randomizados em duplo estudo de infusão contínua de 3 µg/kg/hora de dexmedetomidina ou 5 µg/kg/hora de fentanil, durante anestesia com isofluorano e em ventilaçao mecânica. Parâmetros hemodinâmicos, microcirculatórios, ventilatórios e metabólicos foram utilizados para comparação entre grupos. Esses foram coletados antes da indução anestésica, durante e pós a anestesia. Os dados foram submetidos a teste de normalidade e variâncias iguais, para então avaliar comparativamente os grupos pelo test t student ou Wilcoxon não pareado quando necessário. Todas as variáveis referentes à microcirculação não apresentaram diferença significativa entre os grupos. A infusão contínua de dexmedetomidina apresentou melhores resultados de pressão arterial e clearance de lactato, sugerindo não comprometer o transporte de oxigênio da periferia e perfusão de órgãos, quando comparado com o uso de fentanil, e ainda com semelhantes desfechos clínicos como mortalidade, tempo de extubação e ocorrências de hipotensão ou bradiarritmia. Os valores semelhantes de microcirculação e superiores de pressão arterial demonstram que a dexmedetomidina não compromete a microcirculação em relação ao fentanil, mas mantém a macrohemodinâmica com valores superiores. / One of the common changes in sepsis is microcirculatory disorders can occur even with normal hemodynamic macro parameters. Several protocols are indicated for sepsis anesthesia. A drug commonly used in critically ill patients in humans is dexmedetomidine, a potent and selective alpha 2 agonist with proprietary sedatives, analgesics and muscle relaxant that promotes increased blood pressure and peripheral vasoconstriction. The objective of the present study is to compare the continuous infusion of dexmedetomidine versus fentanyl in septic dogs using three parameters related to microcirculation, hemodynamic parameters and metabolic parameters. Thirty - three bitches with pyometra submitted to OSH therapeutic surgery, and triaged by the quick SOFA score, were evaluated. The animals were randomized into a double study using continuous rate infusion of 3 µg/kg/h dexmedetomidine or 5 µg/kg/h of fentanyl, during isoflurane anesthesia and under mechanical ventilation. Hemodynamic, microcirculatory, ventilatory and metabolic parameters were used for comparison between groups. These were collected prior to anesthetic induction, during and after anesthesia. The data were submitted to normality test and the same variances, and then comparatively evaluate the groups by the unpaired Wilcoxon test t student or when necessary. All variables related to microcirculation did not present significant difference between the groups. The continuous infusion of dexmedetomidine presented better blood pressure and lactate clearance results, suggesting that it did not compromise peripheral oxygen transport and organ perfusion when compared to fentanyl, and with similar clinical outcomes such as mortality, extubation time and occurrences of hypotension or bradyarrhythmia. Similar values of microcirculation and higher blood pressure demonstrate that dexmedetomidine does not compromise microcirculation over fentanyl, but maintains macrohemodynamics with higher values.

To acquire its characteristic structural and functional complexity, the mammalian nervous system must undergo several critical developmental processes. One such process requires factors that regulate the decision of dividing progenitors to leave the cell cycle and activate the neuronal differentiation program. It is shown in this thesis that the murine runt-related gene Runx1 is expressed in proliferating cells on the basal side of the murine olfactory epithelium. Disruption of Runx1 function in vivo does not result in a change in the quantity of progenitors but leads to a decrease in precursor number and an increase in differentiated ORNs. These effects result in premature and ectopic ORN differentiation. Further, exogenous Runx1 expression in cultured olfactory neural progenitors causes an expansion of the mitotic cell population. In agreement with these findings, exogenous Runx1 expression also promotes cortical neural progenitor cell proliferation without inhibiting neuronal differentiation. These effects appear to involve transcriptional repression mechanisms. Consistent with this possibility, Runx1 represses transcription driven by the promoter of the cell cycle inhibitor p21Cip1 in cortical progenitors. Taken together, these findings suggest a previously unrecognized role for Runx1 in coordinating the proliferation and neuronal differentiation of selected populations of neural progenitors/precursors. / Another significant step in the development of the mammalian nervous system is the acquisition of distinctive neuronal traits. This thesis also shows that Runx1 is expressed in selected populations of postmitotic neurons of the murine embryonic central and peripheral nervous systems. In embryos lacking Runx1 activity, hindbrain branchiovisceral motor neuron precursors of the cholinergie lineage are correctly specified but then fail to enter successive stages of differentiation and undergo increased cell death resulting in neuronal loss in the mantle layer. Runx1 inactivation also leads to a loss of selected sensory neurons in trigeminal and vestibulocochlear ganglia. These findings uncover previously unrecognized roles for Runx1 in the regulation of neuronal subtype specification. / This thesis thus presents a novel factor which functions at several steps in the development of the mammalian nervous system and adds to the growing body of work on the processes involved in elaborating such a complex and vital structure.

Le récepteur nucléaire FXR (NR1H4) possède quatre isoformes exprimés principalement dans le foie (FXR[alpha]1 et FXR[alpha]2) et dans l'intestin (FXR[alpha]3 et FXR[alpha]4). Le rôle de FXR dans l'homéostasie des acides biliaires au sein du système digestif est bien documenté. Récemment, de nouvelles fonctions ont été attribuées à FXR dans l'intestin et une étude de ChIP-seq montre que les sites de liaison de FXR dans le génome diffèrent entre le foie et l'intestin. Notre hypothèse de recherche est que FXR contribue au maintien d'un épithélium intestinal intègre et fonctionnel en influençant des processus biologiques autres que la régulation de l'absorption des acides biliaires, et ce, par l'activation de la transcription de nouveaux gènes cibles dans l'intestin. Notre premier objectif consistait en l'identification de nouvelles cibles transcriptionnelles de FXR. Le modèle cellulaire Caco-2/15 est utilisé comme modèle d'entérocytes différenciés et l'expression de FXR augmente lors de la différenciation de ces cellules pour atteindre un niveau maximal vers 20 jours post-confluence. Dans ces cellules bien différenciées, une expérience de micro-puce à ADN révèle que l'activation de FXR par son agoniste synthétique le GW 4064 module significativement l'expression de gènes associés à différents processus biologiques tels l'organisation du cytosquelette et l'adhésion biologique. Nous avons confirmé que l'expression des gènes des protéines structurales MYO1A, MYO7A et DST est régulée positivement par l'activation de FXR, sans doute de manière indirecte puisque nous n'avons pas observé par ChIP que FXR se liait au promoteur de ces gènes. Pour identifier de nouvelles cibles directes de FXR, un criblage par qPCR selon divers critères a été réalisé. Ainsi, nous avons confirmé que le gène de SLC20A1, un transporteur de phosphore, est régulé positivement par l'activation de FXR. De plus, selon nos essais de ChIP, FXR se lie au promoteur de SLC20A1 suggérant une activation directe de la transcription. Ces résultats ouvrent la voie à un rôle auparavant insoupçonné de FXR dans des processus liés à l'absorption du phosphore. Notre deuxième objectif qui était d'étudier la régulation de l'expression différentielle des isoforme de FXR a été réalisé par des essais luciférase et nous amène à croire que le promoteur des isoformes intestinaux est régulé par la présence du facteur de transcription Cdx2. En effet, le promoteur FXR[alpha]3/[alpha]4 présente un site de liaison à Cdx2 contrairement au promoteur FXR[alpha]1/[alpha]2. De plus, en contexte où les facteurs hépatiques et intestinaux HNF1[alpha] et HNF4[alpha] sont présents, Cdx2 rétablit un fort niveau d'activité au promoteur FXR[alpha]3/[alpha]4 et non au promoteur FXR[alpha]1/[alpha]2. Pour conclure, ce projet de recherche montre bien que FXR dans un modèle mimant un contexte physiologique est capable d'activer des gènes cibles jusqu'ici inconnus et que l'expression des isoformes intestinaux est régulée de façon distincte par Cdx2 dans ce tissu.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 3 uppsatser.

Diss. (sammanfattning) Uppsala : Univ., 2002. / Härtill 5 uppsatser.